By his first wife, Fyodor Karamazov sired one son — Dmitri — and by his second wife, two sons — Ivan and Alyosha. None of the Karamazov, boys, however, was reared in the family home. Their mothers dead and their father a drunken fornicator, they were parceled out to various relatives. Fyodor could not have been more grateful; he could devote all energy and time to his notorious orgies. Those were the early years.
Dmitri comes of age, as the novel opens, and asks his father for an inheritance that, he has long been told, his mother left him. His request is scoffed at. Old Karamazov feigns ignorance of any mythical monies or properties that are rightfully Dmitri's. The matter is far from ended, though, for Dmitri and his father find themselves instinctive enemies, and besides quarreling over the inheritance, they vie for Grushenka, a woman of questionable reputation. Finally it is suggested that if there is to be peace in the Karamazov household, the family must go together to the monastery and allow Alyosha's elder, Father Zossima, to arbitrate and resolve the quarrels. Ivan, Karamazov's intellectual son, accompanies them to the meeting.
At the monastery, there seems to be little hope for a successful reconciliation. Fyodor parades his usual disgusting vulgarities, makes a dreadful scene, and when Dmitri arrives late, he accuses his son of all sorts of degeneracy. Dmitri then retorts that his father has tried to lure Grushenka into a liaison by promising her 3,000 rubles, and in the midst of their shouting, Father Zossima bows and kisses Dmitri's feet. This act ends the interview. All are shocked into silence. Later, old Karamazov recovers from his astonishment and once again he makes a disgraceful scene in the dining room of the Father Superior. He then leaves the monastery and commands Alyosha to leave also.
It is now that Dostoevsky reveals that Karamazov perhaps has fathered another son. Years ago, a raggle-taggle moron girl who roamed the town was seduced and bore a child; everyone, naturally, assumed that the satyr-like Karamazov was responsible. The child grew up to be an epileptic and now cooks for Karamazov. He is a strange sort, this Smerdyakov, and lately his epileptic seizures have become more frequent. Curiously, he enjoys talking philosophy with Ivan.
The day after the explosive scene in the monastery, Alyosha comes to visit his father and is stopped midway by Dmitri. The emotional, impulsive Karamazov son explains to Alyosha that he is sick with grief — that some time ago, he became engaged to a girl named Katerina, and has recently borrowed 3,000 rubles from her to finance an orgy with Grushenka. He pleads for Alyosha to speak to Katerina, to break the engagement, and to help him find some way to repay the squandered money so that he can feel free to elope with Grushenka. Alyosha promises to help if he is able.
The young man reaches his father's house and finds more confusion: Smerdyakov is loudly arguing with another servant about religion, spouting many of Ivan's ideas. Later, when the servants are ordered away, Karamazov taunts Ivan and Alyosha about God and immortality, and Ivan answers that he believes in neither. Alyosha quietly affirms the existence of both. Dmitri then bursts into the room crying for Grushenka and when he cannot find her, attacks his father and threatens to kill him.
Alyosha tends his father's wounds, then goes back to the monastery for the night. The next day he goes to see Katerina, as he promised Dmitri, and tries to convince her that she and Ivan love each other and that she should not concern herself with Dmitri and his problems. He is unsuccessful.
Later that same day, Alyosha comes upon Ivan in a restaurant, and they continue the conversation about God and immortality that they began at their father's house. Ivan says that he cannot accept a world in which God allows so many innocent people to suffer and Alyosha says that, although Ivan cannot comprehend the logic of God, there is One who can comprehend all: Jesus. Ivan then explains, with his poem "The Grand Inquisitor," that Jesus is neither a ready nor an easy answer-all for his questionings — that He placed an intolerable burden on man by giving him total freedom of choice.
When Alyosha returns to the monastery, he finds Father Zossima near death. The elder rallies a bit and lives long enough to expound his religious beliefs to his small audience, stressing, above all, a life of simplicity, a life in which every man shall love all people and all things, and shall refrain from condemning others. This is Zossima's final wisdom, and when he finishes, he dies.
Next day many people gather to view the holy man's corpse, for popular rumor has whispered for years that upon Zossima's death, a miracle would occur. No miracle occurs, however. Instead, a foul and putrid odor fills the room, and all of the mourners are horrified. Even Alyosha questions God's justice and, momentarily yielding to temptation, he flees to Grushenka's house. But after he has talked with the girl, he discovers that she is not the sinful woman he sought; she is remarkably sensitive and quite understanding and compassionate. Alyosha's faith is restored and, later, in a dream of Jesus' coming to the wedding of Cana, he realizes that life is meant to be joyously shared. Now he is absolutely certain of his faith in God and in immortality.
Dmitri has meanwhile been frantically searching for a way to raise the money to repay Katerina. He has even gone to a neighboring town to try and borrow the sum, but even there he fails. Returning, lie discovers that Grushenka is no longer at home and panics, sure that she has succumbed to Fyodor's rubles. He goes first to his father's house; then, after discovering that she is not there, he tries to escape but is cornered by an old servant. He strikes him aside, leaving him bloody and unconscious, and returns to Grushenka's house. He demands to know her whereabouts and at last is told that she has gone to join a former lover, one who deserted her five years before.
Dmitri makes a final decision: he will see Grushenka once more, for the last time, and then kill himself. He travels to the couple's rendezvous, finds Grushenka celebrating with her lover, and joins them. There is resentment and arguing, and finally Grushenka is convinced that her former lover is a scoundrel and that it is Dmitri whom she really loves. The two lovers are not to be reunited, however, for the police arrive and accuse Dmitri of murdering his father. Both are stunned by the circumstantial evidence, for the accusation is weighty. Dmitri indeed seems guilty and is indicted to stand trial.
Alyosha, in the meantime, has made friends with a young schoolboy, the son of a man brutally beaten by Dmitri in a rage of passion and gradually the youth has proven his sincere desire to help the frightened, avenging boy. Now that the youngster is dying, Alyosha remains at his bedside, where he hopes to help the family and also to reconcile the young boy with many of his schoolmates.
Ivan, the intellectual, has neither the romantic passion of Dmitri nor the wide, spiritual interests of Alyosha, and when he learns of his father's murder, he broods, then decides to discuss his theories with Smerdyakov. He is astonished at the bastard servant's open confession that he is responsible for the murder. But Smerdyakov is clever; he disavows total responsibility and maintains that Ivan gave him the intellectual and moral justification for the murder and, furthermore, that he actually permitted the act by leaving town so that Smerdyakov would be free to accomplish the deed. Ivan is slow to accept the argument but after he does, he is absolutely convinced of Smerdyakov's logic. The transition is disastrous. His newfound guilt makes him a madman and the night before Dmitri's trial, he is devoured with burning brain fever. That same night, Smerdyakov commits suicide. Dmitri's situation becomes increasingly perilous.
During the trial, the circumstantial evidence is presented in so thorough a manner that Dmitri is logically convicted as Fyodor's murderer. He has the motive, the passion, and was at the scene of the crime. Perhaps the most damning bit of evidence, however, is presented by Katerina. She shows the court a letter of Dmitri's in which he says that he fears he might be driven to murder his father.
After the conviction, Dmitri agrees to certain plans for his escape but says that it will be great torture and suffering for him to flee from Mother Russia, from Russian soil, and to live in exile.
As for Alyosha, his future holds the promise of hope and goodness (qualities that were once never associated with the Karamazovs), for after young Ilusha dies and all his schoolmates attend the funeral, Alyosha gathers them together and deeply impresses them with his explanation of love and of friendship. Spontaneously, the boys rise and cheer Alyosha and his wisdom.